A waste heat recovery system associated with an engine system may include an evaporator in thermal communication with an exhaust stream of an engine. The evaporator may be configured to absorb thermal energy of the exhaust stream and transfer the thermal energy of the exhaust stream to a working fluid flowing through a working fluid conduit associated with the waste heat recovery system. The waste heat recovery system may additionally include a turbine expander located fluidly downstream of the evaporator that may be configured to produce work as the working fluid passes through the turbine expander. Moreover, this system may include a condenser positioned fluidly downstream of the expander and the condenser may condense the vapor phase working fluid leaving the expander into a liquid phase working fluid. Finally, such a system may include a pump located fluidly downstream of the condenser, but fluidly upstream of the evaporator. The pump may be used to propel the working fluid through the waste heat recovery system.
A key aspect of the efficient control of the waste heat recovery system is measuring, and subsequently adjusting, the working fluid mass flowrate. Customarily, waste heat recovery system designers solve this problem by installing a dedicated mass or volumetric flowrate meter, such a Coriolis flowmeter to measure the working fluid mass flowrate or to measure the volumetric flowrate using a turbine or other type of volumetric flowmeter and then calculate the mass flow rate based on the fluid's thermal state. Each of these options is expensive to undertake.
The present disclosure is directed to overcoming one or more problems set forth above and/or other problems associated with known waste heat recovery systems.